7 days after me and my gf had sex and she took plan b one step... she thinks she started her period today but 4 days early maybe because of plan b, her regular period is on the 27 o 28 she has some of her regular period symptoms but we are not sure because she could also have implantation bleeding because it has only pass 7 day after sex and implantation bleeding starts 7 o 12 days after sex... need help period or implantation bleeding...